12mo ago

Leaky Blood Vessels: Underlying Cause of Long COVID “Brain Fog” Discovered

scitechdaily.com Leaky Blood Vessels: Underlying Cause of Long COVID “Brain Fog” Discovered

Scientists uncover crucial links between Long COVID and brain blood vessel integrity, offering hope for new treatments and diagnostic methods. A team of scientists from Trinity College Dublin and investigators from FutureNeuro announced a major discovery that has profound importance for our under

This study shows links between Long COVID’s neurological effects, including brain fog and cognitive decline, and brain blood vessel integrity, offering hope for new treatments and diagnostic methods.

https://www.nature.com/articles/s41593-024-01576-9 (open access)

77 comments

Bringing in a medical perspective since there is a lot of subtle misunderstanding in the comments section:
The source study is not referring to “brain bleeding” or “mini strokes” as a cause of long COVID—the results point more towards a breakdown of the integrity of the blood brain barrier and maybe micro vascular ischemia.
You can essentially think of your central nervous system (brain and spinal cord) as being surrounded by a very selective security system called the Blood Brain Barrier (BBB). The BBB exists to prevent certain chemicals and cell signaling molecules from entering the central nervous system and messing things up. Neurons and many of the cells that support neurons do not regenerate and tolerate stress as well as other parts of the body, which is why the BBB is so important. Through the various assays the primary authors used it seems like in the setting of long COVID there is a breakdown of the BBB—it starts letting things in and out that it shouldn’t be. This leads to inflammation and damage in the brain which likely results in immediate decreased processing ability and also long-term damage (which further leads to decreased processing ability). One of the components which “leaks” in this setting of BBB breakdown are components of the coagulation cascade (the things that make blood clot) which may potentiate small areas of clotting and decreased blood flow (a thing we called micro vascular ischemia—like an ischemic stroke but in very small capillaries). This entire mechanism is similar to (but very different in nuance) “leaky gut syndrome,” where the gut endothelium starts to break down and cause inflammation. I put that out there since leaky gut is gaining more popular understanding these days and may be more familiar for some folks.
As of now there is no available treatment that restores the endothelial integrity of the BBB. Off of the top of my head this study may suggest that more treatments to modulate the inflammsome (roughly—the amount of inflammation in your body) could be beneficial—which sort of tracks since there is some scattered evidence that high dose Omega-3’s help long COVID.
- This is an excellent explanation. Thank you for taking the time to write it.
- Is there a way to check if one has this condition?
  
  Not exactly—although an MRI w/wout contrast may show some microvascular ischemia or cortical volume loss. Based on the study there may be some clues from secondary inflammatory markers, but those aren’t specific (other things can elevate them beyond long COVID).
  I think this will likely remain a clinical diagnosis for several years until we understand more.
- Would you say that the layman's metaphor for this is like the brain suddenly living in a drafty house?
  
  I think in some ways that could work.
  I think a better one may be fish living in a tank that suddenly had its filter break (fish being the brain, and the filter being the BBB).
- Oh this was really very well explained. Thanks a lot for sharing this.
- Thanks

I’ve been waiting since 2021 for my sense of smell and taste to come back :(
- Anecdotal but several of my friends claimed that psilocybin therapy restored their sense of smell.
  
  That is interesting. Psilocybin has been shown to grow new brain neural pathways. It does seems plausible.
  https://www.cell.com/neuron/fulltext/S0896-6273(21)00423-2
  
  Holy crap, now that you mention it, im pretty sure I've felt something similar from shrooms
- Apologies if you've already tried this or something similar, it doesn't work for everyone, but I got mine back by using essential oils to retrain [edited as my phone autocorrected to 'restrain'] my olfactory system. After over a year of my food tasting like trash, or like it was off, and a dangerous incident (with a trip to A&E) where my brain fog meant I left an unlit gas oven on all night and couldn't smell it until I'd already got carbon monoxide poisoning (thankfully mild and temporary), I regained my smell and taste in about a week. Here's an article about it, it links to a charity that works in the field of loss of smell : https://www.saga.co.uk/magazine/health-wellbeing/treatments/smell-training-for-anosmia
  Edit: if the down votes are because people think this is alternative medicine or woo, it isn't, it's a technique used in conventional medicine clinics. Try reading before you down vote.
  
  To educate downvoters: Yes, “essential oil” health advice is a common bullshit indicator! But! They’re the standard pharmaceutical for this task, found in kits like this one used to train food and beverage scientists. Any diverse set of strong familiar smells can work.
  I worked in a related field and got my ass kicked by long COVID shortly after the start of the pandemic. This is a good starter on the biology involved, a journal article from Nature, unpaywalled: https://web.archive.org/web/20220623072436/https://www.nature.com/articles/d41586-022-01628-9
  Treating anosmia from brain damage is the same for post-COVID as for a car accident or getting gassed in WWI: you diligently breathe in the olfactory training kit and try to vividly remember those smells.
  Pull quote: “Sometimes, the sense of smell recovers spontaneously after injury. The olfactory nerve is the only cranial nerve that can repair itself when damaged, and olfactory sensory neurons — cells in the upper part of the nose that recognize different odorant molecules — renew themselves periodically throughout life.“
  edit to add, extreme sympathies to anyone who has found themselves experiencing this!
  e2: corrected link
  
  regarding your edit there, I guess most people stopped reading at 'essential oils' without knowing where this was going.
  this is one (the only?) actual medical use for these things - their main thing is that they smell in a certain way that is consistent, so you use them to retrain your sense of smell. that's it. no taking internally or applying to skin or whatever. just take the stopper off the wee bottle, sniff and repeat for as many bottles as you can be arsed.
  when I had covid-19, I didn't have so well defined scents on hand, but I did have several colognes I could sniff, and I knew fairly well how they were supposed to smell and could use those to gauge my senses. fun times, they were...
  
  Clever! An actual legit medical use for essential oils!
  
  Try reading before you down vote.
  Speaking only for myself, what really threw me off was the following:
  Apologies if you’ve already tried this or something similar, it doesn’t work for everyone, but I got mine back by using essential oils to restrain [emphasis mine] my olfactory system.
  I think that if I'd realized that you meant to say "retrain" here instead of "restrain", I would not have been so quick to initially dismiss it as obviously nonsense.
  
  Sharon Amos has written about gardening for Saga Magazine and The Guardian, among others. She is the author of Plants for Free and Great Plants for Tough Places.
  Sure buddy.

Holy shit I had a mild case of COVID with headaches as my only symptom. I then had long COVID and couldn't think straight, forgot words all the time, had trouble finishing sentences. It's terrifying to think this is why that was happening but it tracks because every time my feet got cold during that same time period one of my toes swelled up. Probably the same thing happening in my foot and my brain.
- Oh wow I've been blaming alcohol abuse on brain fog. I quit drinking last year but still can't remember words all the time, same with finishing sentences. Struggling with being articulate all the time. And this all started during covid.
  
  That could be long COVID but it could also unfortunately be the after effects of heavy drinking. Did your brain issues start after you had COVID?
- This is terrifying. I am 8 weeks in after testing positive. A blood exam reveal no more viral or bacterial infection but I still experience some anxiety and brain fog, today was one of those days (yesterday was an awesome day on the other hand).
  I get cold hands all the time when I am starting to feel unwell.

So this is actually pretty close to what a lot of people thought was going on: mini strokes.

Can it be treated? Does it heal?
- understanding the underlying cause of these conditions will allow us to develop targeted therapies for patients in the future,” said Prof. Matthew Campbell
  Lets hope so. I imagine they might try medicines to reduce the bleeding and improve healing.
- Anecdotally speaking I had covid a few months before vaccination became available (yay) and had horrible brain fog. I forgot a lot of words and really struggled with finishing sentences, things like that. It did improve but it took about a year. At the same time one of my toes kept swelling up every time my feet got cold and that stopped around the same time my ability to think improved.
  
  Thanks for sharing a hopeful anecdote about long COVID, they’re few and far between. I’m glad you got better.

Good god. I had covid twice, once before the vaccines and once after being vaxxed. I had a month of bad brain fog after each. It's terrifying to think I was going to work and driving while my brain was leaking.
- Capitalism's gotta make sure you earn those profits for shareholders. Strokes be damned.
  
  Right!? I was sick for two weeks each time. I couldn't have taken anymore time off. Deep down I knew I probably shouldn't have been working during the worst of the fog but I needed the money.

After covid I had some regular and unusually strong headaches for a while. Maybe my brain was bleeding?
- Unlikely. The most likely answer is that your sinuses never drained and you had a secondary infection.
  But it's possible that leaky blood vessels had some effect. Note that leaky vessels are very different from an actual bleed.
  
  A sinus headache is distinguishable from a regular headache, so I wouldn't discount the leaky blood vessels possibility.
  Good point pointing out the difference between a "leak" and a "bleed," though: if your brain is bleeding, that's a full-blown emergency.

I'm so grateful that I didn't manage to catch COVID
- Yet...
  The virus is far from extinction and isn't going anywhere in our lifetimes.
  Expecting to never catch Covid over the next few decades is like expecting to never catch the common cold.
  
  I think the mutations may be for the better, though. First time I got it (2nd shot), I felt like dogshit. Brain fog, sore muscles, extreme fatigue, runny nose, chills, etc. Second time I got it I felt fine except a small amount of brain fog.
- How do you know you didn't catch it? One of the problems, especially early on, was that some infections were asymptomatic.
  
  Indeed, I'm not sure even testing is sufficient. My family recently got it (my wife and I visiting my parents), but thought nothing of it for a week. My father had a sore throat, my mother had watery eyes and some nasal congestion. My father masked indoors (because I don't want a regular cold either) and chalked my mother's symptoms to seasonal allergies (the cars were covered with Pine pollen all week). Then, on the drive home, my wife felt off. 10 hours in the car together. She slept in the guest room that night and, just for grins, tested for Covid the next morning. She was positive. We called and had my parent's test - both positive. I tested negative so I packed my things and rented a hotel room for the week and worked there alone. I tested every other day and was never positive, but I cancelled all my client meetings.
  I still never "got it" but...is it really feasible I didn't have some low level? This is my second trip in a car for multiple hours with someone who tested positive the next day. Granted, I'm about 4 vaccines in (2xOG, 1 updated, 1 XBB variant), but so is my wife. I have to think that I had some sub-clinical level of viral load, or at least below the antigen test threshold, but I'm thankful I escaped symptoms.
  
  And sometimes mild enough to be mistaken for allergies
- Same. I was so (oddly) proud of my streak. Then my spouse brought it home from a meeting with friends : P
  
  Finally got it for the first time last week, tested positive on my wedding day 😭
  
  :-/
- Have you had any flu like symptoms since 2020?
  Were you vaccinated and boostered?
  Lots of people like to pretend they didn't get it while not actually knowing.
  
  Yeah, this is my 65-year-old aunt. Never got covid she says - and yet she's been sick more than once since 2019. She just never tests - so she never gets covid! Easy!
  
  I've had the flu a few times but whenever I tested (I was quite concerned) I always tested negative. Like 3 separate flus.
- You've indeed been lucky.

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